The present invention relates to controlling a read/write operation to be executed by a slave device on a bus, and more particularly, to an electronic device with enhanced management data input/output control.
Management data input/output (MDIO) interface is specified in the IEEE 802.3 standard and intended to provide a serial interface to transfer management data between a media access control (MAC) layer and a physical (PHY) layer. The MDIO interface includes two pins, a bidirectional MDIO pin coupled to an MDIO bus and a management data clock (MDC) pin coupled to an MDC bus. The MDC is usually provided by a MDIO master and sourced to all MDIO slaves on an MDIO bus controlled by the MDIO master. A device with the MDIO master that controls the MDIO bus is called a station management entity (STA), while a device with the MDIO slave being managed is called an MDIO manageable device (MMD). To put it another way, the STA is embedded in the MAC layer and acts as a master for MDIO interface, and the MMD is embedded in the PHY device and acts as a slave on the MDIO interface. One MDIO master is allowed to be coupled to a plurality of MDIO slaves through an MDIO bus. The MDIO bus is a relatively slow interface. However, its ability to access and modify various registers in PHY devices (i.e., MDIO slaves) by the MDIO master can extend the application of a network device using the MDIO interface.
If the MDIO master is required to send a write command accompanied with the same write data to each of a plurality of MDIO slaves on the MIDO bus, the MDIO master has to send the write command several times due to the fact that the MDIO slaves have different designated physical (port) addresses and a write command for a particular physical (port) address is executed by one of the MDIO slaves only. In addition, there are no error check mechanism and write-incremental function supported by the MDIO interface specified in the IEEE 802.3 standard. Hence, there is a need for an innovative design which is capable of achieving enhanced MDIO control over MDIO slaves on the MDIO bus.